Corrugated reflector



Sam. 29, 1925.

C. E. GODLEY CORRUGATED REFLECTOR Fi1eg1 July 21, 1922 Patented Sept. 29, 1925.

UNITED STATES 1,555,411 PATENT OFFICE.

CHARLES E. GODLEY, 013 DETROIT, MICHIGAN, ASSIGNOR TO EDMUNDS &. JONES CORPORATION, OF DETROIT, MICHIGAN, A CORIORATION OF NEW YORK.

CORRUGATED REFLECTOR.

Application filed July 21, 1922. Serial No. 576,408.

To all whom it may concern:

Be it known that I, CHARLES E. Gown, a citizen of the United States, and residing at Detroit, in the county of Wayne and State of Michigan, have invented a new and Improved Corrugated Reflector, of which the following is a specification.

This invention relates to the construction of reflectors of projecting lamps of the type shown in my prior applications, Ser. Nos. 559,204, dated May 8, 1922, and 562,065, dated May 19, 1922, and has substantially the same object, that is, to so divide the reflector into panels that the rays of light will be projected below the horizontal axis of the lamp upon a clearly defined limited area and in part concentrated upon a restricted portion of such area, but the object of the present invention differs from that of the two prior inventions in that while those were designed to concentrate upon a portion of such area restricted as to both height and width, the present invention is designed to restrict the concentrated rays in height alone, the area of concentrated light having the same width as the area of lesser illumination.

Vehicle head lamps have been provided with reflectors which expand the light beam in a single plane to give a fairly strong illumination to a comparatively short section of the roadway but this illumination is uneven, that portion of the illuminated roadway farthest from the vehicle being less bright than the middle and nearer portions because the illuminating effect of a given light decreases as the square of the distance from the lamp.

The reflector forming the subject matter of this application is provided with a series of panels to widen the beam of light. These panels are curved relative to a vertical plane passing through the focal axes of the two halves of the reflector so as to cause the illuminated field to be nearly rectangular, and the two halves of the reflector are so formed that their focal axes are at an angle to each other in a common vertical plane, and their foci are at different distances from the front edge of the reflector, the plane which divides the reflector into these two halves being horizontal. The result of this is that one of the halves will illuminate a substantially rectangular field of greater width than height and the other half will concentrate its rays on a transverse portion of th1s field of substantially full width but of less height, and because of the divergenceof the axes, this area of double illumination may be at the top of the field. The advantage of this lies in the fact that a reflector of this character can give a much greater degree of illumination to the road- K ay some dlstance in advance of the veic e.

In the accompanying drawing, Fig. 1 is a front elevation of a reflector embodying the present invention. Fig. 2 is a central longitudinal and vertical section thereof. Fig. 3 is a horizontal section thereof. Fig. 4 is a diagram of a field of illumination.

S1milar reference characters refer to like parts throughout the several views.

The reflector 11 is generally paraboloidal in form and after being formed and polished, is placed between proper dies and its surface is scored or corrugated so as to be divided into the panels 13 and 14 which may be of different'widths, those next to the central aperture 12 of the reflector being preferably narrower than those farther away, although these widths may be reversed. Each of these panels may be said to be substantially in a vertical plane and those on each side of the vertical central plane of the reflector being parallel to each other but all of the panels are preferably curved slightly relative to the vertical plane in order to effect the projection of diffused light toward the corners of the main projected field.

The method of obtaining the exact curvatures of the various anels is illustrated and described in my prior application above mentioned. Each anel presents a transversely concave sur ace toward the plane of the open end of the reflector.

The scorings extend continuously across the horizontal line 33 of Fig. 1 which indicates the plane where the two parts 19 and 20 of the reflector unite. The focal point of the lower half 20 of the reflector is at 15 in Fig. 2 and the illumination portion of the filament of the light bulb is also at 15 so that, if the lower half 20 were not corrugated, the area which would be illuminated thereby could be represented on the diagram, Fig. 1, by a semi-circle whose center is at O and whose radius equals the length of two spaces on the diagram. But because of the corrugations, this area of illumination is widened until it reaches to about the vertical lines 9, and because of the curvature of the upper and lower ends of the panels 13 and 14, the lower corneis of this band are quite strongly illuminated.

The focal point of the upper half of the reflector is at 16 and its focal axis 17 makes an angle with the focal axis 18 of the lower half 20. As the focal point 16 is in the rear of the point of illumination, the projected image is reversed and enlarged so that, if the upper half 19 were not corrugated, the illuminated area would be a semicircle having its center at the point 0 in Fig. 4 and a radius .equal to the length of four spaces. But the corrugations and the curvature and the panels again change the area of illumination to substantially a rectangle of substantially even vertical height, the up per border being near the upper border of the area illuminated by the lower half of the reflector.

The two portions of the reflector may be said to be angularly displaced on an axis which is preferably midway between the focal points 15 and 16.

The area between horizontal lines 2 and 4 therefore receives not only the light projected by the lower half 20 but also a portion of the light projected by the upper portion 19 so that it will be much more strongly illuminated. When this reflector is used in the headlamp of an automobile, the rays of light that would fall on the space between horizontal lines 5 and 6 of Fig. 4 will fall on the roadway quite near the vehicle while those which would fall on the space between horizontal lines 2 and 3 illuminate a portion of the roadway considerably in advance of the vehicle. As this amount of light is much greater than that which falls on the space between the lines 5 and 6, the roadway will be much more nearly evenly illuminated than by the use of the well known parabolic reflector. Moreover, by so deforming the reflector that each half projects a beam of rectangular section having its upper edge substantially horizontal, I can readily secure the combination of highly effective road illumination with a horizontal cut off as generally desired both by automobile drivers and by State authorities. So also, by varying the angle between the focal axes of the two halves of the reflector, I can shift the relative projection of the two projected beams, although I prefer to adjust the angle between the focal axes so that the upper edges of the beams coincide and jointly afford a horizontal cut off at the desired height.

In practice it may be found desirable to ease off the corners at the line 3-3 of Fig. 1

between the upper and lower portions of the reflector so that the inner edge of the vertical radial flange shall be a continuous curve, but such changes as well as many others in the sizes and roportions and details of this reflector may be made by those skilled in the art without departing from the spirit of my invention as set forth in the following claims.

I claim 1. A paraboloidal reflector whose reflecting surface is composed of two substantially equal portions joining along a horizontal plane and having different foci and which surfaces are scored to form panels which are concave away from such foci, all the panels being symmetrical relative to the central vertical plane of the reflector and having their ends curved toward said plane.

2. A paraboloidal reflector whose reflecting surface is composed of two substantially equal portions joining along a central horizontal plane and having different foci and whose surfaces are scored to form panels which are concave away from such foci, all the panels being symmetrical relative to the central vertical plane of the reflector and having their ends curved relative thereto, the focal axes of the two portions of the reflector being at an angle to each other, and each axis extending on the opposite side of the central horizontal plane from its portion of the reflector.

3. A paraboloidal reflector whose reflecting surface is composed of two substantially equal portions joining along a horizontal plane and having different foci and whose surfaces are scored to form panels which are concave away from such foci, all the panels being symmetrical relative to the central vertical plane of the reflector and having their ends curved relative thereto, the focal axes of the two portions of the reflector being at an angle to each other in said vertical plane.

4. A paraboloidal reflector whose reflecting surface is composed of two substantially equal portions joining along a horizontal plane and having different foci and whose reflecting surfaces are scored to form panels which are symmetrical in form and arrangement relative to the central vertical plane of the reflector and have their ends curved relative thereto, the focal axes of the two portions of the reflector being at an angle to each other in said vertical plane.

5. A paraboloidal reflector whose reflecting surface is composed of two substantially equal portions joining along a horizontal plane and having different foci and whose surfaces are scored to form panels, the panels on each side of the vertical focal plane of the reflector being parallel to each other and curved so that their middle portions are farther. from said plane than their ends, the

Ill

focal axes of the two portions of the reflector being at an angle to each other and in said vertical focal plane.

6. The combination with a source of light, of a reflector comprising two substantially semi-paraboloidal halves each having its surface so deformed from a true semi-paraboloidal as to widen the beam projected by that portion into a substantially rectangular section, the deforming of each half being 10 two halves having their focal axes intersect- 16 ing at the source of light.

CHARLES E. GODLEY. 

